Conventional automobile transmissions include an oil pump to supply oil to various components within the transmissions. The oil pump can be driven by the engine and/or electric motors. Transmissions include an input shaft that can be coupled to the engine crankshaft. The oil pump can be indirectly driven by the engine through the transmission input shaft.
Rotary lobe pumps and gear pumps can be utilized with conventional automobile transmissions. The pumps include at least two engaging gears or rotors. As the gears engage fluid is pulled in and out of the pump cavity. During cycling the rotors may overheat causing axial or radial expansion and ultimately leading to seizure of the pump. Additionally, just after engine start up, settled debris on the bottom of the torque converter may flow between gears causing congestion between the moving parts. Such congestion can cause abrasive wear of the pump components and negatively impact the overall performance and durability of the pump.
Some pumps include seals to prevent fluid leakage into certain areas of the transmission. However, such seals require a number of additional assembly steps. Moreover, the cost of the seals increase the overall part costs of the pump.
Therefore, it is desirable to have a fluid pump with its own hydraulic circuit designed to reduce the temperature of the gears during operation. Moreover, it is desirable to have a lubricating system that reduces debris within the pump cavity. Also, a fluid pump of lower costs than existing pump designs is desired.